Very happy with Octopus Energy. After four months, time for reflection - there must be some downsides!
Main gripe folks seem to have is Octopus is quite good at building a surplus on your account. The initial DD is taken pretty early, and if you don't update your meter readings monthly a higher guestimate is used. Referral fees are added, but they don't result in lower monthly direct debits it seems - so the balance just grows and grows.
This doesn't mean Octopus is charging more - the rate is exactly as contracted. Though you might be losing out on a trivial amount on interest if it were in a savings account. You have to manually decide when to have a chunk of your balance refunded to your account. Guess that saves on Octopus's bank charges, as well as earning them a little interest.
Octopus Energy came top in Which? Energy Supplier Comparison 2019, beating Bulb and the only one to get five stars from Which? members in every category - prices, complaints procedures, bill accuracy, bill clarity and online customer service.
